U.S. patent number 9,980,209 [Application Number 14/217,914] was granted by the patent office on 2018-05-22 for efficient frequency assignment for mobile devices in coexisting wireless communication systems.
This patent grant is currently assigned to QUALCOMM Incorporated. The grantee listed for this patent is QUALCOMM Incorporated. Invention is credited to Srinivasan Balasubramanian, Jen Mei Chen, Manoj M. Deshpande.
United States Patent |
9,980,209 |
Balasubramanian , et
al. |
May 22, 2018 |
Efficient frequency assignment for mobile devices in coexisting
wireless communication systems
Abstract
Efficient frequency assignment for mobile terminals in
coexisting wireless communication systems is described herein. The
coexisting wireless communication systems comprise a macro
communication system and a localized communication system. Two
prioritized lists are defined, a first list comprising a first
entry relating to the macro communication system and the second
entry relating to the localized communication system, the first and
second entries each listing at least one common frequency. Based on
the first list, a mobile terminal uses communication protocols
associated with the localized communication system.
Inventors: |
Balasubramanian; Srinivasan
(San Diego, CA), Chen; Jen Mei (San Diego, CA),
Deshpande; Manoj M. (San Diego, CA) |
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
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Assignee: |
QUALCOMM Incorporated (San
Diego, CA)
|
Family
ID: |
40998835 |
Appl.
No.: |
14/217,914 |
Filed: |
March 18, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20140213247 A1 |
Jul 31, 2014 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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12392930 |
Feb 25, 2009 |
8682332 |
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61031646 |
Feb 26, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
48/16 (20130101); H04W 8/02 (20130101); H04W
72/00 (20130101); H04W 72/0453 (20130101); H04W
16/16 (20130101); H04W 8/005 (20130101); H04W
48/18 (20130101) |
Current International
Class: |
H04W
4/00 (20180101); H04W 48/16 (20090101); H04W
8/02 (20090101); H04W 8/00 (20090101); H04W
16/16 (20090101); H04W 48/18 (20090101); H04W
72/00 (20090101); H04W 72/04 (20090101) |
Field of
Search: |
;455/432.1,436,434,525,522,502,422.1,552.1,432.2,435.1,435.2,450,550.1,456.1
;370/310,331,395.2,395.52,328,329,338,352 ;709/220,224,227
;348/211.2,211.3,207.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1235443 |
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Nov 1999 |
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CN |
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1427566 |
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Jul 2003 |
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CN |
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1313338 |
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May 2003 |
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EP |
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H04003535 |
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Jan 1992 |
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JP |
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H10190553 |
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Jul 1998 |
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JP |
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2006049972 |
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Feb 2006 |
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JP |
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9914974 |
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Mar 1999 |
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WO |
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Other References
Balasubramanian S et al., "Femto Cells-Search and System
Selection", 3GPP2,S00-FEMTO-20071015-024, Oct. 15, 2007. cited by
applicant .
Fan et al., "Interference Management in Femto Cell Deployment",
3GPP2, S00-FEMTO-20071015-025_QCOM Femto Interference Management,
Oct. 15, 2007. cited by applicant .
International Search Report and Written
Opinion--PCT/US2009/035342--ISA/EPO--dated Oct. 26, 2009. cited by
applicant .
Qualcomm Europe: "Measurement and mobility issues for home (e)Node
Bs" 3GPP Draft; R2-074117, 3rd Generation Partnership Project
(3GPP), Mobile Competence Centre ; 650, Route des Lucioles ;
F-06921 Sophia-Antipolis Cedex; France, vol. RAN WG2, No. Shanghai,
China; 20071008, Oct. 1, 2007 (Oct. 1, 2007), XP050136747 the whole
document. cited by applicant .
Taiwan Search Report--TW098106202--TIPO--dated Aug. 22, 2013. cited
by applicant .
Ch'ng B., et al., "Femto Access Control Provisioning and Enhanced
System Selection," S00-FEMTO-20071015-019, 3GPP2, Oct. 15, 2007.
cited by applicant .
Ch'ng B., et al., "Femto Related Provisioning Enhancements for
Enhanced System Selection (ESS) for Femto Cells", C14-20071203-009,
3GPP2, Dec. 1 2007. cited by applicant.
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Primary Examiner: Hu; Jinsong
Assistant Examiner: Yi; Alexander
Attorney, Agent or Firm: Muncy, Geissler, Olds & Lowe,
P.C.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of U.S. application Ser. No.
12/392,930, filed Feb. 25, 2009, which claims priority under 35 U.
S. C. .sctn. 119 (e) from U.S. Provisional Patent Application No.
61/031,646, filed Feb. 26, 2008, entitled "OPTIMIZED PREFERRED
ROAMING LIST (PRL) BASED APPROACH FOR FEMTO CELL SYSTEM SELECTION"
which are hereby incorporated by reference in their entirety.
Claims
We claim:
1. A method operable by a mobile device, comprising: receiving,
from one or more of a first communication system and a second
communication system, first geographic coordinates defining a
geographic location of the first communication system, second
geographic coordinates defining a geographic location of the second
communication system, and priority indicators indicating the
respective priorities of the first communication system and the
second communication system, wherein the first communication system
and the second communication system are each associated with a
common frequency channel; determining that the first communication
system and the second communication system are both in range of the
mobile device, based on the first geographic coordinates and the
second geographic coordinates; selecting, based on the priority
indicators, a highest-priority communication system from a group
comprising the first communication system and the second
communication system; communicating with the highest-priority
communication system on the common frequency channel; measuring
interference on the common frequency channel at the mobile device;
transmitting interference data to the highest-priority
communication system; and receiving one or more instructions to
communicate on a different frequency channel that is different from
the common frequency channel.
2. The method of claim 1, wherein the receiving of the first
geographic coordinates, second geographic coordinates, and priority
indicators comprises receiving a prioritized list comprising the
first geographic coordinates, second geographic coordinates.
3. The method of claim 2, wherein the prioritized list further
comprises a system identification/network identification (SID/NID)
code for each of the first communication system and the second
communication system.
4. The method of claim 2, wherein one or more of the first
communication system and the second communication system is a first
macro communication system, and the prioritized list further
comprises data relating to a second macro communication system, the
second macro communication system having lower priority than the
first communication system and the second communication system.
5. The method of claim 1, wherein determining that the first
communication system is within range of the mobile device comprises
locating a beacon from the first communication system, and
redirecting communications to a frequency identified by the
beacon.
6. An apparatus, comprising a processor coupled to a memory, the
memory holding program instructions that when executed by the
processor, cause the apparatus to perform: receiving, from one or
more of a first communication system and a second communication
system, first geographic coordinates defining a geographic location
of the first communication system, second geographic coordinates
defining a geographic location of the second communication system,
and priority indicators indicating the respective priorities of the
first communication system and the second communication system,
wherein the first communication system and the second communication
system are each associated with a common frequency channel;
determining that the first communication system and the second
communication system are both in range of the mobile device, based
on the first geographic coordinates and the second geographic
coordinates; selecting, based on the priority indicators, a
highest-priority communication system from a group comprising the
first communication system and the second communication system;
communicating with the highest-priority communication system on the
common frequency channel; measuring interference on the common
frequency channel at the mobile device; transmitting interference
data to the highest-priority communication system; and receiving
one or more instructions to communicate on a different frequency
channel that is different from the common frequency channel.
7. The apparatus of claim 6, wherein the instructions for receiving
of the first geographic coordinates, second geographic coordinates,
and priority indicators further comprise instructions for receiving
a prioritized list comprising the first geographic coordinates, the
second geographic coordinates, and the priority indicators.
8. The apparatus of claim 7, wherein the prioritized list further
comprises a system identification/network identification (SID/NID)
code for each of the first communication system and the second
communication system.
9. The apparatus of claim 7, wherein one or more of the first
communication system and the second communication system is a first
macro communication system, and the prioritized list further
comprises data relating to a second macro communication system
having lower priority than the first communication system and the
second communication system.
10. The apparatus of claim 6, wherein the instructions for
determining that the first communication system is within range of
the mobile device further comprise instructions for locating a
beacon from the first communication system, and redirecting
communications to a frequency identified by the beacon.
11. An apparatus, comprising: means for receiving, from one or more
of a first communication system and a second communication system,
first geographic coordinates defining a geographic location of the
first communication system, second geographic coordinates defining
a geographic location of the second communication system, and
priority indicators indicating the respective priorities of the
first communication system and the second communication system,
wherein the first communication system and the second communication
system are each associated with a common frequency channel; means
for determining that the first communication system and the second
communication system are both in range of the mobile device, based
on the first geographic coordinates and the second geographic
coordinates; means for selecting, based on the priority indicators,
a highest-priority communication system from a group comprising the
first communication system and the second communication system;
means for communicating with the highest-priority communication
system on the common frequency channel; means for measuring
interference on the common frequency channel at the mobile device;
means for transmitting interference data to the highest-priority
communication system; and means for receiving one or more
instructions to communicate on a different frequency channel that
is different from the common frequency channel.
12. A non-transitory computer-readable medium comprising codes for
causing a computer to: receive, from one or more of a first
communication system and a second communication system, first
geographic coordinates defining a geographic location of the first
communication system, second geographic coordinates defining a
geographic location of the second communication system, and
priority indicators indicating the respective priorities of the
first communication system and the second communication system,
wherein the first communication system and the second communication
system are each associated with a common frequency channel;
determine that the first communication system and the second
communication system are both in range of the mobile device, based
on the first geographic coordinates and the second geographic
coordinates; select, based on the priority indicators, a
highest-priority communication system from a group comprising the
first communication system and the second communication system;
communicate with the highest-priority communication system on the
common frequency channel; measure interference on the common
frequency channel at the mobile device; transmit interference data
to the highest-priority communication system; and receive one or
more instructions to communicate on a different frequency channel
that is different from the common frequency channel.
13. The non-transitory computer-readable medium of claim 12,
wherein the codes for receiving of the first geographic
coordinates, second geographic coordinates, and priority indicators
further comprise codes for causing the computer to receive a
prioritized list comprising the first geographic coordinates, the
second geographic coordinates, and priority indicators.
14. The non-transitory computer-readable medium of claim 12,
wherein the prioritized list further comprises comprise a system
identification/network identification (SID/NID) code for each of
the first communication system and the second communication
system.
15. The non-transitory computer-readable medium of claim 12,
wherein one or more of the first communication system and the
second communication system is a first macro communication system,
and the prioritized list further comprises data relating to a
second macro communication system, having lower priority than the
first communication system and the second communication system.
16. The non-transitory computer-readable medium of claim 12,
wherein the codes for causing the computer to determine that the
first communication system is within range of the mobile devices
further comprises codes for causing the computer to locate a beacon
from the first communication system, and redirecting communications
to a frequency identified by the beacon.
Description
BACKGROUND
Field
The present application relates generally to wireless
communications, and more specifically to methods and systems for
efficient frequency assignment for mobile devices in coexisting
wireless communication systems.
Background
Wireless communication systems are widely deployed to provide
various types of communication (e.g., voice, data, multimedia
services, etc.) to multiple users. As the demand for high-rate and
multimedia data services rapidly grows, there lies a challenge to
implement efficient and robust communication systems with enhanced
performance.
In recent years, users have started to replace fixed line
communications with mobile communications and have increasingly
demanded great voice quality, reliable service, and low prices.
In addition to mobile phone networks currently in place, a new
class of small base stations has emerged, which may be installed in
a user's home and provide indoor wireless coverage to mobile units
using existing broadband Internet connections. Such personal
miniature base stations are generally known as localized
communication systems, access point base stations, Home Node B's
(HNB's), or femtocells. Typically, such miniature base stations are
connected to the Internet and the mobile operator's network via DSL
router or cable modem.
A prioritized list such as a Preferred Roaming List (PRL) is a
database residing within many wireless devices, such as cellphones,
that contains information used during the process of system
selection and acquisition. In the case of RUIM-based CDMA devices,
the PRL resides on the RUIM. The PRL indicates which bands, sub
bands and service provider identifiers will be scanned and in what
priority order. Without a PRL, the device may not be able to roam,
i.e. obtain service outside of the home area. There may be cases
where missing or corrupt PRL's can lead to a customer not having
service at all.
On many networks, regularly updating the PRL is advised if the
subscriber uses the device outside the home area frequently,
particularly if they do so in multiple different areas. This allows
the phone to choose the best roaming carriers, particularly
"roaming partners" with whom the home carrier has a cost-saving
roaming agreement, rather than using non-affiliated carriers. PRL
files can also be used to identify home networks along with roaming
partners, thus making the PRL an actual list that determines the
total coverage of the subscriber, both home and roaming
coverage.
The PRL is built by an operator and is normally not accessible to
the user. Many operators provide the ability for the user to
download the latest PRL to their device by dialing the Over-the-air
(OTA) feature code *228.
A typical PRL structure consists of an acquisition table and a
system table (along with some header and overhead information). The
acquisition table comprises an indexed list of frequencies on which
the device may search for particular systems. The idea behind the
acquisition table is to optimize the acquisition time by
identifying only the frequencies that should be searched, rather
than searching the entire frequency spectrum. The information
contained in each acquisition table entry includes an index, the
network type, and associated channel blocks.
The system table generally comprises a prioritized list of systems
that the device is permitted to access (Preferred Systems) and
those that it is explicitly forbidden to access (Negative Systems).
Note that it is also possible to indicate forbidden systems using a
separate system identification number/network identification number
(SID/NID) Lockout List in the handset; however, this is not a
recommended approach as it creates control over system selection
outside of the PRL.
Each system table entry belongs to a geographic area known as a
GEO. These GEOs are listed in priority order. Each
IS-95/1.times.RTT system is identified by either SID/NID or, in the
case of enhanced PRL, SID/NID or MCC/MNC. To support 1.times.EV-DO
systems, the PRL must be IS-683-C or later. Each 1.times.EV-DO
system is identified by a Subnet ID. For hybrid mode operation
(i.e. IS-95/1.times.RTT and 1.times.EV-DO), association tags are
used link an IS-95/1.times.RTT system with one or more
1.times.EV-DO systems. Hybrid systems always attempt to select an
IS-95/1.times.RTT system first, then use the association tag to
attempt to select an associated 1.times.EV-DO system.
Each entry also provides an acquisition table index where the
frequencies associated with that system are identified and a
roaming indicator that dictates what type of indication should be
displayed to the user when they are receiving service from that
system.
The PRL typically operates in one of two modes, a restrictive mode
or a permissive mode, dictated by a Preferred Only indicator. In
the restrictive mode, otherwise known as the closed PRL or
Preferred Only Mode, the device will only acquire systems
identified as preferred in the PRL system table. While this mode of
operation gives operators the most control over the system
selection process, it requires that PRLs be kept up-to-date to
ensure that newly added roaming partners can be selected. Note that
even if a PRL is restrictive according to the preferred only
indicator, the use of wildcard SID/NID or MCC/MNC values as
preferred systems would essentially make the PRL permissive because
wildcards match any system that is located.
In the permissive mode, otherwise known as the open PRL or Not
Preferred Mode, the device will attempt to acquire preferred
systems. However, if no preferred systems can be located, the
device may select systems that are not listed in the PRL system
table. It still will not select negative systems; but, if no
preferred systems can be found and an unknown system is available,
it will select the unknown system. While this mode of operation is
easier to maintain because new partners can be chosen even if they
are not explicitly listed in the PRL, it carries with it the danger
of allowing the mobile device to become camped onto a system that
will not provide it with service. Further information on PRL is
defined by OTASP specification TIA-683, available from the 3GPP2
website as C.S0016.
Prior mechanisms used for a UE to access femtocells include using
beacons deployed on all macro carriers (i.e., carrier signals
emanating from cellular communication systems), a PRL mechanism
within the UE that lists the femtocell as the most preferred system
with all the macro channels treated as equal, or using the macro
system to send one or more SRDMs (redirection messages) to move the
mobile to a femto-channel associated with a femtocell.
One shortcoming of the aforementioned methods to access femtocells
is that a significant amount of power may be consumed by a UE
attempting to locate and connect with a femtocell. Therefore, there
is a need to enable UEs to locate and connect to femtocells while
minimizing power requirements to do so.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an exemplary wireless communication system;
FIG. 2 illustrates an exemplary communication system to enable
deployment of access point base stations within a network
environment;
FIG. 3 illustrates a block diagram of a communication system having
a mobile station or user equipment for scanning and acquiring a
small base station;
FIG. 4 illustrates a methodology or sequence of operations
illustrating some possible states of a femto-enabled mobile station
moving into coverage areas of macro systems and various types of
small base stations;
FIG. 5 is an illustration of a system that can interface mobile
devices with a cellular network by way of a network of femto base
stations;
FIG. 6 illustrates a sample mobile device such as the one described
in FIGS. 3 and 4;
FIG. 7 is a flow diagram illustrating a method for assigning
frequencies to mobile devices operating in coexisting communication
systems;
FIG. 8a illustrates a first simplified prioritized list;
FIG. 8b illustrates a second simplified prioritized list;
FIGS. 9a and 9b illustrate alternative, exemplary, prioritized
lists used in one embodiment;
FIG. 10 illustrates a flow diagram illustrating a method for
efficient frequency assignment for a mobile terminal
assignment;
FIG. 11 illustrates a system operator facility for assigning
frequencies to mobile devices operating in coexisting communication
systems;
FIG. 12 illustrates an apparatus for frequency assignment to mobile
terminals in coexisting communication systems used in a mobile
terminal;
FIG. 13 illustrates an apparatus for frequency assignment to mobile
terminals in coexisting communication systems used by a macro
system operator; and
FIG. 14 illustrates another embodiment of an apparatus for
frequency assignment to mobile terminals in coexisting
communication systems.
SUMMARY
Methods and apparatus are described for efficient frequency
assignment for wireless devices in coexisting communication
systems, such as in a macro communication system and a localized
communication system. In one embodiment, a method is described
comprising receiving a prioritized list of related frequency and
network identification information, the prioritized list comprising
at least two entries; a first entry relating to a macro
communication system and the second entry relating to a localized
communication system, the first and second entries each listing at
least one common frequency. Next, one or more searches for the
localized communication system is conducted using the common
frequency while using the common frequency to communicate with the
macro communication system. Next, the localized communication
system is used for communications on the common frequency when the
localized communication system is determined to be in range.
In another embodiment, a method is described for efficient
frequency assignment for mobile terminals in coexisting
communication systems comprising defining a common frequency to be
used by a first macro communication system and a localized
communication system. Further, a first prioritized list of related
frequency and network identification information is generated, the
first prioritized list comprising at least two entries, a first
entry relating to the macro communication system and the second
entry relating to the localized communication system, the first and
second entries each listing the common frequency. A second
prioritized list of related frequency and network identification
information is generated, the second prioritized list comprising at
least one entry relating to the macro communication system and no
entries relating to the localized communication system. Finally,
the first prioritized list is provided to a first mobile terminal
authorized to communicate using either the macro communication
system or the localized communication system, and the second
prioritized list is provided to a second mobile terminal, the
second mobile terminal not authorized to communicate using the
localized communication system.
In yet another embodiment, a method is described, comprising
engaging in an active communication by a mobile device with a macro
communication system using a first frequency that is common to both
the macro communication system and a localized communication
system. Then, if interference from the localized communication
system is greater than a predetermined threshold, instructions are
received to transfer the active communication to a second frequency
based on the interference level exceeding the predetermined
threshold.
Various apparatus are also described which implements the
aforementioned methods.
DETAILED DESCRIPTION
The word "exemplary" is used herein to mean "serving as an example,
instance, or illustration." Any embodiment described herein as
"exemplary" is not necessarily to be construed as preferred or
advantageous over other embodiments. The disclosed embodiments may
be applied to any one or combinations of the following
technologies: Code Division Multiple Access (CDMA) systems,
Multiple-Carrier CDMA (MC-CDMA), Wideband CDMA (W-CDMA), High-Speed
Packet Access (HSPA, HSPA+), Time Division Multiple Access (TDMA)
systems, Frequency Division Multiple Access (FDMA) systems,
Orthogonal Frequency Division Multiple Access (OFDMA) systems, or
other multiple access techniques. A wireless communication system
may be designed to implement one or more standards, such as IS-95,
cdma2000, IS-856, W-CDMA, TD-SCDMA, and other standards.
In embodiments described in detail below, a macro cellular network
is enabled to build a required prioritized list or preferred
roaming list (PRL) based on an International Mobile Subscriber ID
(IMSI) of the primary household member with and without storing it
in a separate database. As the macro network changes, updated PRL
configurations are pushed to the femto UE. Since these are
dedicated PRL configurations, the GEO table can be structured to be
as small as possible also. Thus, the existing PRL update mechanisms
can be relied upon. The access point base station or femtocell does
not need to be involved. In addition, these embodiments avoid
storing information within the database and allow for the PRL to be
derived based on the identification of the primary household
member. The derived key associated with the primary household
member is retained to address the scenario when the primary
household member moves and the same key is further reassigned to
another member in the household.
Throughout this specification, the terms "network" and
"sub-network" are used interchangeably and represent a
communication system in the former and a sub-set of the
communication system in the latter.
FIG. 1 illustrates an exemplary wireless communication system 100
configured to support a number of users, in which various disclosed
embodiments and aspects may be implemented. The wireless
communication system 100 is referred to herein a macro
communication system, macro network, or simply macro and simply
refers generally to any cellular-based wireless communication
system.
As shown in FIG. 1, by way of example, macro cell mobile network
100 provides communication for multiple cells 102, such as, for
example, macro cells 102a-102g, with each cell being serviced by a
corresponding access point (AP) 104 (such as APs 104a-104g). Each
cell may be further divided into one or more sectors. Various
access terminals (ATs) 106, including ATs 106a-106k, also known
interchangeably as user equipment (UE), mobile terminals, or mobile
devices, are dispersed throughout the system. Each AT 106 may
communicate with one or more APs 104 on a forward link (FL) and/or
a reverse link (RL) at a given moment, depending upon whether the
AT is active and whether it is in soft handoff, for example. The
macro cell mobile network 100 may provide service over a large
geographic region, for example, macro cells 102a-102g may cover a
few blocks in a neighborhood.
FIG. 2 illustrates an exemplary localized communication system 200
coexisting with the communication system of FIG. 1. In other words,
the coverage areas of communication system 100 and communication
system 200 overlap to some degree. The localized communication
system 200 employs access point base stations, otherwise known as
Home Node B units (HNBs), or femtocells, within a network
environment that provide limited range communications for mobile
devices operating in proximity to a femtocell. As shown in FIG. 2,
the system 200 may include multiple access point base stations, or
Home Node B units (HNBs), such as, for example, HNBs 210, each
being installed in a corresponding small scale network environment,
such as, for example, in one or more user residences 230, and being
configured to serve associated, as well as alien, user equipment
(UE) 220. Each HNB 210 is generally coupled to the Internet 240 and
a mobile operator core network 250 via a DSL router (not shown) or,
alternatively, a cable modem (not shown). The system 200 is
referred to herein as a localized communication system or network,
because it generally does not provide a large coverage area,
especially when compared to the macro cell mobile network 100.
Although embodiments described herein use 3GPP terminology, it is
to be understood that the embodiments may be applied to 3GPP2
(1.times.RTT, 1.times.EV-DO Re10, RevA, RevB) technology and other
known and related technologies. In such embodiments described
herein, the owner of the HNB 210 subscribes to a mobile service,
such as a 3G mobile service, offered through the mobile operator
core network 250. The UE 220 is generally capable of operating in
both a macro cellular environment and in a residential small scale
network environment. Thus, the HNB 210 is generally backward
compatible with any existing UE 220.
A femto UE 220 is defined as a mobile device, or UE, that is
capable of operating with the macro cell mobile network 100 or a
femtocell 210, based on software upgrades or through general
provisioning. In one embodiment, a femto UE 220 operates on the
macro cellular network 100 and, with several available frequencies
to choose from, will monitor a frequency to which it has been
assigned by, typically, a hashing function. While monitoring and/or
using the assigned frequency, a femto UE (or UE's in general)
typically perform a search for other, more desirable systems using,
for example, a technique known in the art as BSR. The BSR technique
is used every so often (typically in terms of minutes) to search
for other, more desirable communication networks (including
femtocells) by searching frequencies other than the one that is it
currently monitoring. This is generally a power-consuming process.
It would be advantageous to avoid off-frequency searching for
femtocells in range of a mobile device.
With the above in mind, an operator of the macro communication
system 100 may choose to assign one or more frequencies to be a
shared frequency between system 100 and system 200. What this means
for a mobile device having dual-system communication provisioning
is that if the mobile device is monitoring the shared frequency in
a macro mode of communications, it does not have to go "off
frequency" to find a femtocell, thereby saving power and
computational resources of the mobile device.
One issue that will confront a system operator desiring to use the
shared frequency technique discussed above is that the system
operator may want to restrict some mobile devices from being able
to access one or more femtocells. One way to do this is to assign
different prioritized lists of available networks and/or
sub-networks to each mobile device.
In FIG. 3, a communication system 300 enables a femto UE, wireless
terminal, wireless device, mobile station, or user equipment (UE)
302 to increase its access to a core network 304 to areas not
served by a macro base station (e.g., evolved Base Node (eNB)) 306
by using a localized communication system or small base station
(e.g., femtocell) 308. Femtocells can be placed within a structure
310 that degrades reception of the eNB 306. The femtocell as often
owned by end user 312 and interface to the core network 304 by a
broadband network (e.g., Internet) 314 can provide an economic
advantage over usage fee rates for using the eNB 306 as a Radio
Access Technology (RAT). Moreover, increasingly users rely upon
wireless communication access at their place of employment or at
home rather than having a landline telephone or other communication
device.
In an illustrative telecommunication system 300, a localized
communication system or femtocell 308, originally known as an
Access Point Base Station, is a small cellular base station,
typically designed for use in residential or small business
environments. It connects to the service provider's network via
broadband (e.g., Digital Subscriber Line (DSL) or cable); current
designs typically support five (5) to one hundred (100) mobile
phones in a residential setting. A femtocell allows service
providers to extend service coverage indoors, especially where
access would otherwise be limited or unavailable. The femtocell
incorporates the functionality of a typical base station but
extends it to allow a simpler, self contained deployment. An
example is a UMTS femtocell containing a Node B, Radio Network
Controller (RNC) and GPRS Support Node (SGSN) with Ethernet for
backhaul. Although much attention is focused on UMTS, the concept
is applicable to all standards, including GSM, CDMA2000, TD-SCDMA
and WiMAX solutions. For a mobile operator, the attractions of a
femtocell are improvements to both coverage and capacity,
especially indoors. There may also be opportunity for new services
and reduced cost. The cellular operator also benefits from the
improved capacity and coverage but also can reduce both capital
expenditure and operating expense. Femtocells are an alternative
way to deliver the benefits of Fixed Mobile Convergence (FMC). The
distinction is that most FMC architectures require a new
(dual-mode) handset which works with existing home/enterprise Wi-Fi
access points, while a femtocell-based deployment will work with
existing handsets but requires installation of a new access
point.
Advantageously, the UE 302 may be provisioned with a location
determination component 316 to determine when proximate to the
femtocell 308 for which authorization is available for open use. If
present, a small base station (SBS) access data structure 318 is
updated and referenced to determine if the femtocell 308 is on a
"white list" 320 of accessible femtocells or is on a "gray list" of
restricted use (e.g., 911 emergency use) 320 or "black list" 322 of
being inaccessible, the latter cases depicted by an alien femtocell
323.
UE 302 can identify the associated femtocell 308 by a geographic
location message 324 broadcast by the femtocell 308.
Advantageously, a movement tolerance component 326 of the UE 302
can identify the associated femtocell 308 even if moved slightly,
changing the reported geographic location. In addition, a defined
coverage area 328 of the femtocell 308 can be area based or three
dimensional (e.g., spherical, polygonal. The SBS access data
structure 318 can further support a defined coverage area 328
including vertical portions of a building. Alternatively or in
addition to geographic location message 324, UE 302 can receive
geographic location 330 from the macro base station (eNB) 306. For
instance, the eNB 306 can send a neighbor list 332 that contains
white list, gray list or black list information. As another
example, the UE 302 can perform location estimates based upon
power/direction or triangulation performed based upon one or more
eNBs 306. Alternatively or in addition, the UE 302 can receive
geographic location 334 based upon reception of global positioning
system (GPS) satellites 336.
The UE 302 may extend its battery service life by using DTX/DRX
transceiver 331 that discontinuously transmits and receives,
supporting improved scan and acquisition of femtocells 308. In
addition, this improved scanning and acquisition provides a
select-right paradigm of acquiring femtocells, including addressing
different usage models, support for multiple femtocells, finding a
femto EV-DO system associated with the femto 1.times. system,
acquiring a femtocell when no or limited macro coverage is
available, and/or supporting an EV-DO-only femtocell that does not
have a 1.times. system. An SBS access data structure provides a
corresponding support. With the provisioned information, procedures
in the mobile station (UE) 302 can efficiently select the femtocell
308. In particular, the mobile can learn the white and black list
information for femto pilot signals in a network.
In one aspect, detect and break system selection loops executed by
the UE 302 are supported to address the issue of femto
identification using existing air-interface standards which do not
explicitly have `femto` ID broadcast messages. Such ID information
is needed for the UE 302 to determine the identity of the femto
308, 322 and to check if the femto 306, 322 is blacklisted,
white-listed, or not appearing in any list. In addition, such
aspects address the issue of protecting a mobile-learned femto
identity entry or a white list or blacklist entry from over-riding
by the network or from deletion by the network.
In one particular aspect, the latitude and longitude information
broadcasted by a cell is used to help identify whether the cell is
a femtocell (as opposed to a macro-cell 306). Such information
could then be stored in the mobile station (MS) or UE 302 so that
the next time the UE 302 sees the same femtocell (identified by the
latitude and longitude and possibly other information), the 302 may
recognize the femtocell (and immediately determine if the femtocell
is a valid femtocell or not--based on the stored information in its
blacklist/white list, for example. In another aspect, of a mask
length is used to help "round out" or roughen the precision of the
longitude and latitude information. For example, each could use 24
bits. A mask length could indicate which of the LSB should be
ignored. Alternatively, a distance determination can be made from
known femtocells with a threshold applied. The need for rounding
out is that the femtocell-transmitted longitude and latitude
information could change on the order of micrometers, centimeters,
etc. (e.g. if a femtocell 308 on table was lightly bumped as
depicted at 338). In an illustrative aspect, the femtocell 308 has
GPS capability and had such GPS information broadcasted by the
femtocell 308. Such mask at the UE 302 provides a means to help the
UE 302 recognize that the femtocell 308 with slightly moved
longitude/latitude (lat/long) information is still the same
femtocell. In additional aspects, finer identification of a
femto-cell 308 (e.g., ideally for unique femto-cell identification)
are supported by additional femto-cell identifiers.
Further enhancements are provided that supporting manual system
selection with human-readable femto identification (e.g., for
manual black list/white list management and manual scans/scans for
a femto-cell. This is depicted as a user interface 340 of the UE
302 that provides a manual learn control 342 as well as an access
indicator 344 that gives feedback as to the type of access (e.g.,
macro, open femto, restricted, unknown femto requiring
authentication codes). Thereby, a mobile handset display control
functions are provided that relate to femto access. Version control
can be provided for SBS access data structure (e.g., Preferred User
Zone List (PUZL) databases). Advantageously, database management
can be provided for partitioning contents (e.g., user zones) into
two sections with one for network-provisioned information and
second for mobile-learned information. Support can also be provided
for active call hand-offs.
FIG. 4 illustrates a methodology or sequence of operations 400
illustrating some possible states of a femto-enabled mobile station
or UE moving into coverage areas of macro systems and various types
of small base stations (e.g., femtocells). In state 402, the mobile
station is not associated with a macro or femto system, and thus
performs a scan for a macro/femto channel based upon relative
priority (block 404). If the mobile station finds a femto system as
depicted at 406, then a state 408 is entered where in the mobile
station is associated with a femto system, which in the
illustrative depiction is the most preferred system (block 410). If
loses the femto coverage as depicted at 412, then the mobile
station returns to state 402. Should the mobile then find a macro
system based upon relative priority as depicted at 414, then a
state 416 is entered wherein the mobile station is associated with
a macro system but is not in any user zone. In an exemplary aspect,
cost can be decreased by finding an open user zone, so the mobile
station continues to identify one or more user zones associated
with the macro-SID from the PUZL database (block 418). A check is
made to see if the mobile station (MS) has entered the user zone(s)
based upon finer definitions of scan regions (e.g., RF coverage
based and/or geographic-based entries) (block 420).
If the mobile station enters a specific user zone as depicted at
422, then a state 424 is entered wherein the mobile station is
associated with a macro system identified to be in one or more user
zones. The mobile station executes power/computation efficient
scans to find the femto system(s) associated with the user zone(s)
(block 426) and continually checks to see if the trigger conditions
for the femto system scans remain satisfied (block 428). For
instance, the frequency of checks can be of higher frequency since
the mobile station expects to acquire a preferred femto system. By
contrast, back at block 420, the checks can be relatively
infrequent made in relation to the mobility of the mobile station.
If the mobile station finds a femto system as depicted at 430, then
state 408 is entered. Otherwise, if the mobile station leaves the
user zone as depicted at 432, then state 416 is entered. It also
should be appreciated that one or more of the operations described
herein may not be employed in a given implementation.
FIG. 5 is an illustration of a system 500 that can interface mobile
devices (504) with a cellular network (not depicted) by way of a
network of fBS devices. System 500 includes an fBS 502 (e.g.,
access point) with a receiver component 510 that receives signal(s)
from mobile device(s) 504, or from other fBS devices (not depicted)
through one or more receive antennas 506. fBS 502 also includes a
transmission component 526 that transmits to the mobile device(s)
504 (or other fBS devices) through one or more transmit antennas
508. Receiver component 510 can receive information from receive
antennas 506 and can further comprise a signal recipient (not
shown) that receives uplink data transmitted by the mobile devices.
It should be appreciated that receiver component 510 and
transmission component 526 can both include WLAN, BPL, Ethernet,
UMTS TDD, or WLAN over UMTS TDD spectra communication capabilities
in order to interact with mobile devices or with other fBS
devices.
Receiver component 510 is operatively associated with a demodulator
512 that demodulates received information. Demodulated symbols are
analyzed by a network processor 522 that can generate additional
signals (e.g., in the form of transmission and/or routing
instructions) modulated by modulator 524 and transmitted by
transmission component 526. Further, network processor 522 can be
coupled to a memory 520. Memory 520 stores information pertinent to
effectuating wired and/or wireless communication, application
modules (514, 516) for maintaining an fBS network and routing
information between fBS devices and/or with connected mobile
devices, and/or any other suitable information related to
performing the various actions and functions set forth herein (see
below).
Network processor 522 can route at least a portion of traffic
associated with a communication link between fBS 502 and a mobile
device (504) to a neighboring fBS (not depicted) for transfer to a
cellular network (e.g., by way of a direct connection to the
cellular network, or by way of the Internet). Furthermore, network
processor 522 is configured to direct traffic affiliated with the
fBS 502 (e.g., generated by a predetermined mobile device or group
of mobile devices, for instance) directly to the cellular network
by way of an IP upload link 530 (e.g., DSL connection, such as
ADSL, VDSL, HDSL etc., cable IP connection, BPL connection). In
addition, data can be received from the cellular network via an IP
download link 528 (e.g., DSL, cable, BPL) and directed to a mobile
device (504) affiliated with the fBS 502.
Memory 520 can contain application modules that generate
instructions for forming, maintaining and/or routing data within an
fBS network. Specifically, memory 520 can include an inter-fBS
application module 514 for directing cellular related traffic
between the fBS 502 and a neighboring fBS (not depicted).
Additionally, memory 520 can contain an inter-fBS connectivity
application that maps connectivity between fBS 502 and the
neighboring fBS(s) to compile a connectivity map 518 (e.g., that
can be routed to a cellular network RNC for hand-off and multi-hop
management). Such a connectivity map 518 can establish
contemporaneous propagation, load, QoS or availability parameters,
or a combination of these or like parameters, associated with fBS
502 or the neighboring fBS, or both. In addition, varying levels of
such parameters associated with both voice or data traffic can be
compiled within the connectivity map 518.
In addition to the foregoing, receiver component 510 and
transmission component 526 can receive and transmit, respectively,
various information to/from a cellular network (e.g., via IP upload
530 and/or IP download 528) or to/from other fBS devices of the fBS
network by way of an IP router 527 that communicates over
unlicensed frequencies or wired connections (e.g., WLAN router, LAN
router, or the like). For example, receiver component 510 can
receive an fBS network map from a cellular network RNC that
indicates inter-fBS connectivity parameters for each fBS on the fBS
network. Such parameters can be utilized to coordinate multi-hop
routing of cellular traffic from within the fBS network.
Additionally, instructions for such routing or for managing a soft
hand-off with mobile device(s) 504 can be received from the RNC.
Additionally, inter-fBS connectivity parameters can be received
from other fBS devices themselves (e.g., because of a broadcast
transmission query generated by network processor 522 and
transmitted by transmission component 526). In such a case,
inter-fBS connectivity application 516 can include connectivity
parameters associated with other networked fBS devices into a
connectivity map (described above). The connectivity map can then
be utilized by network processor 522 to direct soft hand-off and/or
multi-hop routing as described herein.
FIG. 6 illustrates a sample mobile device such as the one described
in FIGS. 3 and 4 that can interface with an fBS network for
cellular access in accordance with one or more embodiments. Mobile
device 600 includes at least one antenna 602 (e.g., a transmission
receiver or group of such receivers comprising an input interface)
that receives a signal (e.g., containing information related to a
data link between a first fBS and mobile device 600) and at least
one receiver 604 that performs typical actions (e.g., filters,
amplifies, down-converts, etc.) on the received signal.
Specifically, antenna(s) 602 can receive information from one or
more cellular base stations or fBSs (not depicted), as described
herein, to participate in a communication link with such devices.
For example, the antenna(s) 602 can receive a connectivity map from
an fBS or a cellular network component that provides
contemporaneous indication of transmission quality at various fBS
access points in range of the antenna(s) 602.
Antenna 602 and receiver 604 can also be connected to a demodulator
606 that can demodulate received symbols and provide them to a
processor 608 for evaluation. Processor 608 can be a general
purpose processor dedicated to analyzing information received by
antenna(s) 602 and/or generating information for transmission by a
transmitter 620. Additionally, processor 608 can control one or
more components of mobile device 600, and/or analyze information
received by antenna(s) 602, generate information for transmission
by transmitter 620, and control one or more components of mobile
device 600. Additionally, processor 608 can access an application
module 612 stored in device memory 610 to execute instructions for
directing an fBS device to route traffic to other networked fBS
devices (e.g., where at least one of the other networked fBS
devices is dedicated to carrying traffic associated with mobile
device 600). As a result, processor 608 can facilitate cellular
hand-off in an fBS network environment.
In addition to the foregoing, processor 608 can include
instructions to forward received data to one or more fBS devices
within data that is broadcast by transmitter 620 (e.g., either
directly or by way of another fBS). For instance, processor 608 can
facilitate broadcasting a second portion of cellular traffic that
can be received by at least a second fBS dedicated to carry such
traffic for the mobile device 600 (e.g., by determining that the
second fBS is in range of the mobile device 600). Alternatively,
processor 608 can direct the second portion of data to be
transmitted to a third fBS and direct the third fBS to route the
data to the second fBS (e.g., by way of the instructions included
within the broadcast data). Instructions can be generated based on
contemporaneous transmission parameters associated with the fBS
devices.
Mobile device 600 can additionally comprise device memory 610 that
is operatively coupled to processor 608 and that can store data to
be transmitted, received, and the like. Furthermore, memory 610 can
store application modules for mobile device 600. Application module
612 and transmission mapping application 614 can be two such
modules stored within device memory 610 (see below).
It will be appreciated that a data store (e.g., device memory 610)
described herein can be either volatile memory or nonvolatile
memory, or can include both volatile and nonvolatile memory. By way
of illustration, and not limitation, nonvolatile memory can include
read only memory (ROM), programmable ROM (PROM), electronically
programmable ROM (EPROM), electronically erasable PROM (EEPROM), or
flash memory. Volatile memory can include random access memory
(RAM), which acts as external cache memory. By way of illustration
and not limitation, RAM is available in many forms such as
synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM
(SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM
(ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).
Memory (e.g., device memory 610) of the subject systems and methods
is intended to comprise, without being limited to, these and any
other suitable types of memory.
Application module 612 can be stored in device memory 610 and
configured to generate instructions for an fBS to route cellular
traffic to neighboring fBSs. For instance, the application module
612 can access data store in memory (610) and identify an fBS
affiliated with mobile device 600. An instruction can be generated
and sent (e.g., by processor 608, modulator 618 and/or transmitter
620) to the fBS network identifying the affiliated fBS device and
requesting traffic be forwarded to such device for transfer to a
cellular network. In addition, routing instructions can be
generated by application module 612 based on contemporaneous
transmission parameters of one or more fBSs in the fBS network
(e.g., determined by transmission mapping application 614).
Particularly, application module 612 can reference the transmission
parameters and determine a most efficient route to direct traffic
from a receiving fBS to the affiliated fBS.
Also stored in device memory 610 is a transmission mapping
application 614. The transmission mapping application 614 can be
configured to monitor propagation, load, QoS, availability, power
consumption, or interference parameters, or a combination of these
or like parameters, associated with wireless communication between
mobile device 600 and an fBS network. For instance, transmission
mapping application 614 can monitor transmission information
received at antenna 602 and/or sent by transmitter 620, determine
parameters pertinent to mobile device 600, and compile a
transmission map 616 based on the monitored parameters. In
addition, the transmission mapping application 614 can generate
queries that can be forwarded to one or more fBS devices in the fBS
network. Responses to such queries can be utilized to modify the
transmission map 616 to include transmission information pertaining
to various fBS devices. Alternatively, or in addition, a query can
be sent to an fBS aggregator to receive transmission information
related to the fBS network compiled at an associated cellular
network. Further, the transmission map 616 can be updated
periodically to create a dynamic map indicating contemporaneous
transmission characteristics. The transmission map 616 can then be
referenced to determine suitable fBS access points based on such
dynamic parameters.
Mobile device 600 still further comprises a modulator 618 and a
transmitter 620 that transmits a signal (e.g., including a
transmission data packet) for instance, to a base station (e.g.,
fBS or group of fBSs), an access point, another mobile device, a
remote agent, etc. Although depicted as being separate from the
processor 608, it is to be appreciated that application module 612
and transmission mapping application 614 can be part of processor
608 or a number of processors (not shown), stored in cache memory,
for instance.
FIG. 7 is a flow diagram illustrating a method for a system
operator to assign frequencies to mobile devices operating in
coexisting communication systems, such as a macro cell mobile
network 100 and a localized communication system 200. The steps
shown in FIG. 7 may be accomplished using the hardware shown in
FIG. 11, although one skilled in the art will readily understand
that many other hardware and/or software configurations could be
defined to implement the process of FIG. 7.
In step 700, at least one common frequency is defined that is used
by both the macro communication system 100 and the localized
communication system 200. In step 702, a first prioritized list of
related frequency and network identification information is
generated by a system operator. The first prioritized list
comprises at least two entries; a first entry relating to the macro
communication system 100 and the second entry relating to the
localized communication system 200. The first and second entries
each list the common frequency, as shown in FIG. 8a. Next, as shown
in step 704, a second prioritized list of related frequency and
network identification information is generated, the second
prioritized list comprising at least one entry relating to the
macro communication system 100 and no entries relating to the
localized communication system 200. In step 706, the first
prioritized list is provided to a first mobile device authorized to
communicate using either the macro communication system or the
localized communication system, and in step 708, the second
prioritized list is provided to a second mobile device, the second
mobile device not authorized to communicate using the localized
communication system. Of course, the system operator generally will
provide the first and second lists to many mobile devices, some of
which are authorized to communicate with either macro communication
system 100 or localized communication system 200, and some only
authorized to communicate with the macro communication system
100.
Prioritized lists are well-known in the art for allowing a mobile
terminal or UE to select the best communication option from any
network/sub-network available to it in a current operating area
according to the strategy specified, generally, by roaming business
rules. A PRL is typically provided to a mobile terminal either
during a provisioning state or updated over the air by a user of
the mobile device. The prioritized list is typically a file that is
stored in a portion of memory in a mobile device.
The aforementioned prioritized list generally comprises entries of
frequencies and associated network and/or sub-network
identification information, each entry having a priority code
assigned to it. The priority codes instruct mobile devices to use
an associated network/sub-network and/or frequencies based,
typically, on costs of operation on any particular network. The
prioritized list generally contains information pertaining to one
or more macro communication systems (i.e., a CDMA system operated
by Verizon Wireless, a CDMA system operated by Sprint
Communications, a TDMA system operated by T-Mobile Communications,
or a GSM system operated by AT&T, etc) using well-known SID/NID
codes.
As mentioned above, a system operator wishing to implement the
shared frequency concept will provide one type of prioritized list
to mobile devices having dual-system capabilities (i.e., macro
system and femtocell) and another type to mobile devices that are
forbidden from accessing femtocells. A first type of prioritized
list that is provided to mobile devices having dual-system
capabilities is shown in FIG. 8a while FIG. 8b shows a simplified
prioritized list that is provided to mobile devices prohibited from
accessing femtocells associated with the shared frequency
identified in the prioritized list of FIG. 8a.
The prioritized list of FIG. 8a comprises information pertaining to
at least one localized communication system (such as a femtocell),
i.e., frequency information, network/system identifiers (SID/NID
codes), priority numbers, etc. In particular, FIG. 8a shows three
entries, each entry having a frequency column, a
network/sub-network identifier column, and a priority column. Other
information that may be included in a prioritized list pertaining
to this first embodiment has been omitted for clarity. It should be
understood that the prioritized list may have a greater, or fewer,
number of entries than that shown in FIG. 8a. It should also be
understood that the identifier column typically lists well-known
SID/NID codes identifying particular communication systems and
their sub-systems or networks. For example, in FIG. 8a,
SID.sub.M/NID.sub.M1 might represent a network (NID.sub.M1) in a
CDMA communication system operated by Verizon Wireless (SID.sub.M)
while SID.sub.M/NID.sub.M2 might represent a second network
operating in the same CDMA communication system operated by Verizon
Wireless. The SID.sub.M/NID.sub.F represents a localized
communication system, such as a femtocell. It should be understood
that in other variations of FIG. 8a, there could be more than one
macro cell mobile network defined.
The frequency column lists one or more frequencies in which the
mobile terminal will to hash to. The frequencies are typically used
to communicate system overhead information to/from mobile devices.
For example, the frequencies listed in FIGS. 8a and 8b may
represent frequencies relating to a paging channel. The mobile
device will generally hash to one of the frequencies listed in the
prioritized list to listen for a page directed to the particular
mobile terminal. The page typically includes frequency and/or
channel information for the mobile device to use during an active
communication, such as for transmitting and receiving voice or
data. The frequency used by the mobile device during periods of
active communications may be different than any of the frequencies
listed in the prioritized list. When the active communication
session is over, the mobile device will generally hash to one of
the frequencies listed in the prioritized list.
Referring back to FIG. 8a, entry number 3 shows four possible
frequencies to hash to if the mobile terminal is currently
operating within a coverage area defined by SID.sub.M/NID.sub.M1
and the mobile device is not in range of any other communication
systems. If, however, the mobile terminal determines that it is in
the operating range of both SID.sub.M/NID.sub.M1 and
SID.sub.M/NID.sub.M2, the priority indicators would dictate that
the mobile terminal hash to frequency F5 belonging to
SID.sub.M/NID.sub.M2, rather than SID.sub.M/NID.sub.M1 Similarly,
if the mobile terminal is in the operating range of
SID.sub.M/NID.sub.M1, SID.sub.M/NID.sub.M2, and
SID.sub.M/NID.sub.F, the priority indicators would dictate that the
mobile device hash to frequency F5 belonging to
SID.sub.F/NID.sub.M2, defining a femtocell within range of the
mobile device.
It should be noted that in FIG. 8a, frequency F5 is listed as an
available hash-to frequency for both the macro communication system
(defined by SID.sub.M/NID.sub.M2) and a femtocell (defined by
SID.sub.F/NID.sub.M2). However, it should also be noted that the
priority for frequency F5 is a higher "1" for the femtocell while
being a lower priority "2" for the macro communication system. What
this means is that if the mobile terminal is operating in an area
in which both the macro communication system and the femtocell are
available, the mobile terminal will generally select entry number
one, hash to frequency F5, and monitor/use one or more
communication channels associated with the femtocell. If, however,
the mobile terminal was operating in an area covered by a macro
communication system defined by SID.sub.M/NID.sub.M1 and a macro
communication system defined by SID.sub.M/NID.sub.M2, the mobile
would select entry number 2 (based on priority), hash to frequency
F5 (the same frequency used by the femtocell), but monitor/use one
or more channels associated with a macro communication system
(i.e., a base station associated with a macro communication
system).
In a slight variation of the first embodiment, again using FIG. 8a,
a mobile terminal may first select entry number two (based on
currently available networks and the priority level), monitoring a
macro communication system over frequency F5. If the mobile
terminal next moves in range of a femtocell also operating on
frequency F5, the mobile terminal may switch to communications
using the femtocell by using well-known Idle HandOff principles
such as BSR. For example, the mobile terminal may switch to the
femtocell if a PSMM signal indicates that a pilot signal from the
femtocell exceeds a certain threshold.
In another embodiment, when a mobile device is monitoring the
shared frequency, the mobile device may receive a beacon, or pilot
signal, that may support sync and paging as well. The beacon
conveys information pertaining to the existence of a femtocell
within range of the mobile device. The beacon is transmitted in the
same footprint as the femtocell over a channel other than the
channel of the femtocell operation, typically coinciding with the
macro channel of operation. In this case, while monitoring the
shared frequency (F5 in this case) in a macro mode of
communications (i.e., using communication protocols in accordance
with the macro cell mobile system 100), the mobile device receives
a beacon from a femtocell over frequency F5. In another embodiment,
the mobile device may receive the beacon while monitoring other one
or more frequencies other than the shared frequency. The beacon
comprises of a Pilot, Sync, and Paging channels that allows the
mobile to be redirected to the femto channel of operation, allowing
the mobile to acquire the femtocell. When a mobile device detects a
pilot signal from a beacon in excess of a predetermined threshold,
the mobile performs an Idle Handoff to the beacon and is mandated
to read the overhead information transmitted by the beacon as with
any newly acquired pilot. In one embodiment, a CCLM message (CDMA
Channel List Message) is received by the mobile device over the
paging channel. In another embodiment, a GSRDM/SRDM message
((Global)Service Redirection Message) is received. These messages
are used by the mobile device to move the mobile to a frequency
specified in the message, i.e., to a frequency used by the
femtocell.
FIGS. 9a and 9b illustrate exemplary prioritized lists used in the
embodiment just discussed above. In FIG. 9a, table 900 illustrates
one arrangement of the prioritized list, showing frequencies F5 and
F6 as belonging to the same femtocell and having a priority of "1",
i.e., the highest priority. In another, alternate, arrangement,
FIG. 9b shows table 902 frequency F5 as belonging to the macro cell
mobile network 100 and having a priority of "1", while frequency
F6, belonging to the localized communication system or femtocell,
is shown as also having the highest priority. In another
arrangement, F6 is not listed in the prioritized list.
FIG. 8b shows a prioritized list that is provided to mobile devices
that are not permitted to access a femtocell that operates on the
designated shared frequency, in this case, frequency F5. It should
be understood that a greater number of entries could be defined in
the prioritized list of FIG. 8b. In addition, each entry in the
prioritized list of FIG. 8b may contain a greater, or fewer, number
of frequencies. In this case, only one entry is shown, listing
frequencies F2, F2, F3, and F4 pertaining to SID.sub.M/NID.sub.M1
(although, in other examples, the prioritized list may comprise
more than one entry, each entry having one or more hash-to
frequencies pertaining to the same or other macro cell networks).
Mobile terminals that have been provided the list of FIG. 8b will
hash to one of the frequencies listed in the prioritized list based
on the available networks and/or sub-networks in its current
operating area and a priority level associated with each entry in
the prioritized list. A system operator provides the prioritized
list of FIG. 8a to mobile devices having dual-system permission and
the prioritized list of FIG. 8b to mobile devices not having
dual-system permission.
It should be understood that a system operator may have many
variations of the prioritized lists shown in FIGS. 8a, 8b, 9a, and
9b to be provided to a number of different wireless devices. For
example, a system operator may define a number of prioritized lists
like the one shown in FIG. 8a, each list identifying one or more
frequencies dedicated as a shared channel. The shared frequency(s)
listed in one of the prioritized lists may be the same or different
than shared frequencies defined in other lists. In addition, a
system operator may define any number of prioritized lists like the
one shown in FIG. 8b, each list designating only macro cell
frequencies available to mobile devices. Each of these lists may
have a different number of entries and different number of
frequencies defined for each entry.
FIG. 10 illustrates a flow diagram of an embodiment for efficient
frequency assignment for mobile terminals in coexisting wireless
communication systems, comprising a macro communication system and
a femtocell. References to a mobile terminal will be associated
with FIG. 6.
In step 1000, a prioritized list is received by receiver 604, for
example, in a mobile terminal 600 able to communicate over a macro
network and a femtocell and, in this example, has information
stored therein as shown in FIG. 8a. The prioritized list comprises
information relating to at least one macro communication system and
a femtocell. For example, in FIG. 8a, the third entry comprises
multiple frequency indicators (representing a number of frequencies
that the mobile device may hash to), a third network/sub-network
identifier associated with the multiple frequency indicators, and a
third priority indicator. A second entry might comprise a second
frequency indicator (more than one may be defined), a second
network/sub-network identifier, and a second priority indicator,
the second entry corresponding to the macro network. The first
entry comprises the second frequency indication, a first network
and/or sub-network identifier, and a first priority indicator, the
third entry corresponding to the femtocell. It should be understood
that the second frequency is used by both the macro communication
system and the femtocell and is referred to herein as a common
frequency. Typically, a macro communication system planning effort
assigns frequencies to the various base stations and femtocells
belonging to a particular service provider and, in such a case, the
common frequency between the macro communication system and the
femtocell is pre-arranged. In other embodiments, it might be
coincidental that a femtocell and a macro communication system use
the same frequency.
In any case, the prioritized list is received by a mobile device
able to communicate over the macro communication system or the
femtocell, shown as step 1000. The prioritized list may be saved in
memory device 612. The prioritized list may be provisioned at the
time of manufacture of the wireless device or it may be provided at
any other time. For example, a prioritized list may be provided
over-the-air to a wireless device upon a user of the wireless
device entering a predetermined feature code, such as *228.
Alternatively, the prioritized list may be provided to the wireless
device by using a cable connected between a computer and the
wireless device to directly download the prioritized list into the
wireless device.
After the prioritized list is received, the processor 608 will
search for the localized communication system on the common
frequency while using the common frequency to communicate with the
first macro communication system, shown as step 1002. In step 1004,
at least processor 608 and transmitter 620 are used to communicate
with the localized communication system using the common frequency
when the localized communication system is determined to be in
range.
Other possible actions taken by a mobile terminal 600 in relation
to the process shown in FIG. 10 are described as follows. Once the
prioritized list has been provided to the wireless device, the
wireless device may determine, at some point, one or more available
networks within range of the mobile terminal using techniques
generally known to those skilled in the art. For example, in FIG.
6, this could be accomplished by a combination of receiver 604,
processor 608, and device memory 612. With respect to FIG. 3, it
could be accomplished using location determination unit 316 (as
well as a processor and a memory inherent in mobile terminal
600).
Processor 608 will select a frequency to use and a communication
type (i.e., macro or femto) based on the available networks within
range of the mobile terminal and the priority indicators contained
within the prioritized list as stored in device memory 612. For
example, if two networks are within range of the mobile device, the
mobile device will consult the prioritized list to determine which
of the two networks it is allowed to use (if any) and, if both
networks are allowed, which network has been assigned a higher
priority. The mobile device will then generally hash to one of the
frequencies listed in the prioritized list belonging to the
selected system/sub-system. If one of the systems/sub-systems found
by the mobile device comprises the shared frequency F5, the mobile
will begin monitoring F5. In one embodiment, the mobile device
monitoring frequency F5 does so using protocols in accordance with
macro cell mobile network 100. In another embodiment, the mobile
device discovers a femtocell transmitting on frequency F5 and so
begins monitoring frequency F5 in accordance with protocols
associated with the femtocell or localized communication system
200.
In the embodiment in which the mobile device is monitoring the
shared frequency F5 and communicating with the macro cell mobile
network 100, the mobile device may attempt to find a femtocell or
localized communication system 200 (or a femtocell beacon) within
range of the wireless device using well-known handoff techniques,
such as BSR or typical idle handoff procedures. This is
accomplished by using processor 608 in combination with codes
stored within device memory 612 for performing the above action.
Advantageously, the mobile device continues to use the shared
frequency F5 to search for a localized communication system thereby
eliminating the need to switch frequencies to search for a
femtocell.
When a femtocell is discovered, the mobile device will continue to
monitor/use frequency F5, however it will begin to communicate with
the femtocell, rather than the macro cell mobile network 100, due
to the higher priority level (priority 1) of the femtocell listed
in the prioritized list.
In another embodiment, there may be cases in such a coexisting
communication system as described above in which a mobile terminal
may be actively participating in a communication with the macro
cell mobile network 100 on one particular frequency and receive
interference from a localized communication system 200, or
femtocell, operating on the same frequency. In this case, it is not
desirable or perhaps even possible to transfer a communication in
progress from the macro cell mobile network 100 to a femtocell. For
example, the mobile terminal may be unauthorized or physically
unable to communicate with a localized communication system, or the
particular localized communication system may be off limits to the
particular mobile terminal.
In any case, a mobile terminal, such as mobile terminal 600, may be
engaged in a first active communication with the macro
communication system using a first frequency that is common to both
the macro communication system and the localized communication
system, as described earlier. The mobile terminal may experience
high levels of interference if it is located near a second mobile
terminal or a femtocell operating on the common frequency. The
mobile terminal will detect and measure the interference level,
based on techniques well-known in the art, and compare the measured
interference exceeds a predetermined threshold. For example, the
mobile terminal of FIG. 6 might use processor 608 in conjunction
with receiver 604, device memory 612 in order to perform the
measurement and comparison.
If the measured interference exceeds the predetermined threshold,
the mobile terminal transmits an indication of this event to the
macro cell mobile network 100 using, for example, transmitter 620.
In another embodiment, the mobile terminal simply transmits the
measured interference level to the macro cell mobile network 100
without determining whether the interference level exceeds a
predetermined threshold. In this case, the comparison is done at
the macro infrastructure, for example, by a processor located
within the macro cell mobile network 100.
The mobile terminal will then receive instructions, via receiver
604, to transfer the active communication to a second macro
frequency based on the interference level exceeding the
predetermined threshold. This is generally accomplished by
processor 608 transferring the communication in progress to a
different frequency using techniques well-known in the art. The
instructions to move the active communication to a second frequency
are generally provided by network equipment located within mobile
operator core network 250 after being alerted by the mobile device
that an interference level has been exceeded in the current
frequency of operation. However, in another embodiment, the mobile
terminal may have such instructions predetermined and stored within
device memory 612.
FIG. 11 illustrates a hardware system used by a macro system
operator for assigning frequencies to mobile devices operating in
coexisting communication systems. Shown is system 1100, comprising
processor 1102, storage device 1104, user interface 1106,
transmitter 1208, and UE interface 1110. It should be understood
that all of the components shown in FIG. 11 are not necessary for a
system operator to assigning frequencies to mobile devices
operating in coexisting communication systems. Some of the
components are shown as they would appear in various embodiments of
system 1100.
System 1100 generally comprises a user interface 1106 that receives
information from a macro system operator to define at least one
frequency common to the macro communication system and a localized
communication system, such as a femtocell. In another embodiment,
user interface 1106 comprises hardware and/or software to connect
to a computer that performs various macro system calculations,
generally in regard to system-wide properties, such as frequency
allocation, roaming lists, base station information, etc. In either
case, the common frequency is generally chosen in accordance with
system-wide planning principles and generally requires information
relating to at least one femtocell, such as the operating frequency
of the femtocell.
The processor 1102 receives the common frequency information from
the user interface and generates a first prioritized list of
related frequency and network identification information, the first
prioritized list comprising at least two entries. The first entry
relates to the first macro communication system and the second
entry relates to the localized communication system. The first and
second entries each list the at least one common frequency. An
example of such a list is illustrated in FIG. 8a. The processor
1102 may, in addition, use information stored in storage device
1104 to generate the first prioritized list.
Processor 1102 also generates a second prioritized list of related
frequency and network identification information, the second
prioritized list comprising at least one entry relating to the
first macro communication system and no entries relating to the
localized communication system. An example of such a list is shown
in FIG. 8b. Again, processor 1102 may use information stored in
storage device 1104 to generate the second prioritized list.
The first list is provided to mobile terminals authorized to
communicate with the macro communication system or the localized
communication system. This may be accomplished by providing the
list to UE Interface 1110, generally used during the provisioning
stage of mobile terminal production, where mobile terminals are
initially provided programming information so that they by be
usable when purchased by consumers. UE Interface 1210 comprises any
well-known interface between processor 1202 and a mobile terminal
in the provisioning stage of production.
In addition to UE Interface 1110, or alternatively, the first list
may be provided over-the-air to a mobile terminal using transmitter
1108. This is a well-known technique for provided information
over-the-air to a mobile terminal upon a user of the wireless
device entering a predetermined feature code, such as *228.
The second list is provided to a mobile terminal that is not
authorized to communicate using the localized communication system.
The second list is provided to the non-authorized mobile terminal
in either, or both, of the ways mentioned previously using
transmitter 1108 and/or UE interface 1110.
FIG. 12 illustrates an apparatus 1200 for frequency assignment to
mobile terminals in coexisting communication systems. Apparatus
1200 generally resides at least partially within user equipment
(UE). It is to be appreciated that apparatus 1200 is represented as
including functional blocks, which can be functional blocks that
represent functions implemented by a computing platform, processor,
software, or combination thereof (e.g., firmware). It should also
be understood that not all of the functional blocks shown in FIG.
12 may be necessary for implementing various aspects of the various
embodiments discussed herein.
Apparatus 1200 includes a logical grouping 1202 of electronic
components that can act in conjunction. For instance, logical
grouping 1202 can include one or more electronic components 1204
for receiving a prioritized list of related frequency and network
identification information, the prioritized list comprising at
least two entries, a first entry relating to a first macro
communication system and a second entry relating to a localized
communication system, the first and second entries each listing at
least one common frequency. Apparatus 1200 additionally includes
one or more electronic components 1206 for searching for the
localized communication system on the common frequency while using
the common frequency to communicate with the first macro
communication system. Finally, apparatus 1200 includes one or more
electronic components 1208 for communicating with the localized
communication system using the common frequency when the localized
communication system is determined to be in range.
Apparatus 1200 may additionally include one or more electronic
components 1210 for determining that a localized communication
system is within range of a wireless terminal. In addition,
apparatus 1200 may comprise one or more electronic components 1212
for locating a beacon from the localized communication system, and
one or more electronic components 1214 for redirecting
communications to a frequency identified by the beacon, the
frequency associated with the localized communication system.
Finally, apparatus 1200 may include a memory 1216 that retains
instructions for executing functions associated with electronic
components 1204-1214. While shown as being external to memory 1216,
it is to be understood that the one or more electronic components
1204-1214 can exist within memory 1216.
FIG. 13 illustrates an apparatus for frequency assignment to mobile
terminals in coexisting communication systems used by a macro
system operator. Apparatus 1300 generally resides at least
partially within mobile operator core network 250. It is to be
appreciated that apparatus 1300 is represented as including
functional blocks, which can be functional blocks that represent
functions implemented by a computing platform, processor, software,
or combination thereof (e.g., firmware). It should also be
understood that not all of the functional blocks shown in FIG. 13
may be necessary for implementing various aspects of the various
embodiments discussed herein.
Apparatus 1300 includes a logical grouping 1302 of electronic
components that can act in conjunction. For instance, logical
grouping 1302 can include one or more electronic components 1304
for defining a common frequency to be used by a first macro
communication system and a localized communication system.
Apparatus 1300 further includes one or more electronic components
1306 for generating a first prioritized list of related frequency
and network identification information, the first prioritized list
comprising at least two entries, a first entry relating to the
first macro communication system and the second entry relating to
the localized communication system, the first and second entries
each listing the common frequency, and for generating a second
prioritized list of related frequency and network identification
information, the second prioritized list comprising at least one
entry relating to the first macro communication system and no
entries relating to the localized communication system. Apparatus
1300 further includes one or more electronic components 1308 for
providing the first prioritized list to a first mobile device
authorized to communicate using either the first macro
communication system or the localized communication system, and for
providing the second prioritized list to a second mobile device,
the second mobile device not authorized to communicate using the
localized communication system. Finally, apparatus 1300 may include
a memory 1310 that retains instructions for executing functions
associated with electronic components 1304-1308. While shown as
being external to memory 1310, it is to be understood that the one
or more electronic components 1304-1308 can exist within memory
1310.
FIG. 14 illustrates another embodiment of an apparatus for
frequency assignment to mobile terminals in coexisting
communication systems. Apparatus 1400 generally resides at least
partially within user equipment (UE). It is to be appreciated that
apparatus 1400 is represented as including functional blocks, which
can be functional blocks that represent functions implemented by a
computing platform, processor, software, or combination thereof
(e.g., firmware). It should also be understood that not all of the
functional blocks shown in FIG. 14 may be necessary for
implementing various aspects of the various embodiments discussed
herein.
Apparatus 1400 includes a logical grouping 1402 of electronic
components that can act in conjunction. For instance, logical
grouping 1402 can include one or more electronic components 1404
for engaging in an active communication by a mobile device with a
macro communication system using a first frequency that is common
to both the macro communication system and a localized
communication system. Apparatus 1400 further comprises one or more
electronic components 1406 for detecting interference greater than
a predetermined threshold, the interference originating from the
localized communication system. Apparatus 1400 further comprises
one or more electronic components 1408 for receiving instructions
to transfer the active communication to a second frequency based on
the interference level. Finally, apparatus 1400 may include a
memory 1410 that retains instructions for executing functions
associated with electronic components 1404-1408. While shown as
being external to memory 1410, it is to be understood that the one
or more electronic components 1404-1408 can exist within memory
1410.
While the specification describes particular examples of the
present invention, those of ordinary skill can devise variations of
the present invention without departing from the inventive concept.
For example, the teachings herein refer to circuit-switched network
elements but are equally applicable to packet-switched domain
network elements.
Those skilled in the art will understand that information and
signals may be represented using any of a variety of different
technologies and techniques. For example, data, instructions,
commands, information, signals, bits, symbols, and chips that may
be referenced throughout the above description may be represented
by voltages, currents, electromagnetic waves, magnetic fields or
particles, optical fields or particles, or any combination
thereof.
Those skilled in the art will further appreciate that the various
illustrative logical blocks, modules, circuits, methods and
algorithms described in connection with the examples disclosed
herein may be implemented as electronic hardware, computer
software, or combinations of both. To clearly illustrate this
interchangeability of hardware and software, various illustrative
components, blocks, modules, circuits, methods and algorithms have
been described above generally in terms of their functionality.
Whether such functionality is implemented as hardware or software
depends upon the particular application and design constraints
imposed on the overall system. Skilled artisans may implement the
described functionality in varying ways for each particular
application, but such implementation decisions should not be
interpreted as causing a departure from the scope of the present
invention.
The various illustrative logical blocks, modules, and circuits
described in connection with the examples disclosed herein may be
implemented or performed with a general purpose processor, a
digital signal processor (DSP), an application specific integrated
circuit (ASIC), a field programmable gate array (FPGA) or other
programmable logic device, discrete gate or transistor logic,
discrete hardware components, or any combination thereof designed
to perform the functions described herein. A general-purpose
processor may be a microprocessor, but in the alternative, the
processor may be any conventional processor, controller,
microcontroller, or state machine. A processor may also be
implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
The methods or algorithms described in connection with the examples
disclosed herein may be embodied directly in hardware, in a
software module executed by a processor, or in a combination of the
two. A software module may reside in RAM memory, flash memory, ROM
memory, EPROM memory, EEPROM memory, registers, hard disk, a
removable disk, a CD-ROM, or any other form of storage medium known
in the art. A storage medium may be coupled to the processor such
that the processor can read information from, and write information
to, the storage medium. In the alternative, the storage medium may
be integral to the processor. The processor and the storage medium
may reside in an ASIC.
In one or more exemplary embodiments, the functions described may
be implemented in hardware, software, firmware, or any combination
thereof. If implemented in software, the functions may be stored on
or transmitted over as one or more instructions or code on a
computer-readable medium. Computer-readable media includes both
computer storage media and communication media including any medium
that facilitates transfer of a computer program from one place to
another. A storage media may be any available media that can be
accessed by a computer. By way of example, and not limitation, such
computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or
other optical disk storage, magnetic disk storage or other magnetic
storage devices, or any other medium that can be used to carry or
store desired program code in the form of instructions or data
structures and that can be accessed by a computer. Also, any
connection is properly termed a computer-readable medium. For
example, if the software is transmitted from a website, server, or
other remote source using a coaxial cable, fiber optic cable,
twisted pair, digital subscriber line (DSL), or wireless
technologies such as infrared, radio, and microwave, then the
coaxial cable, fiber optic cable, twisted pair, DSL, or wireless
technologies such as infrared, radio, and microwave are included in
the definition of medium. Disk and disc, as used herein, includes
compact disc (CD), laser disc, optical disc, digital versatile disc
(DVD), floppy disk and blu-ray disc where disks usually reproduce
data magnetically, while discs reproduce data optically with
lasers. Combinations of the above should also be included within
the scope of computer-readable media.
The previous description of the disclosed examples is provided to
enable any person skilled in the art to make or use the present
invention. Various modifications to these examples will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other examples without departing
from the spirit or scope of the invention. Thus, the present
invention is not intended to be limited to the examples shown
herein but is to be accorded the widest scope consistent with the
principles and novel features disclosed herein.
* * * * *